MMR Vaccination Schedule for Children
Yes, a child requires two doses of measles-containing vaccine (MMR) after the age of 1 year for complete protection. 1, 2
First Dose Recommendations
- The first dose of MMR vaccine should be administered at 12-15 months of age as part of routine childhood immunization 1, 2
- The minimum age for MMR vaccination is 12 months 2
- For children who missed the routine schedule, the first dose can be administered up to 12 years of age 2
- For the first dose at age 12-47 months, either MMR vaccine plus separate varicella vaccine or the combination MMRV vaccine may be used 1
- When considering MMRV for the first dose in children 12-47 months, providers should discuss the benefits and risks with parents, noting that MMRV is associated with a higher risk of fever and febrile seizures compared to separate MMR and varicella vaccines 1
Second Dose Recommendations
- The second dose of MMR vaccine is routinely recommended at age 4-6 years (before kindergarten or first grade entry) 1, 2
- This timing for the second dose has been jointly adopted by ACIP, the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) 1
- The second dose may be administered earlier than 4 years of age, provided at least 28 days (4 weeks) have elapsed since the first dose 1, 2
- For the second dose at any age (15 months-12 years), MMRV vaccine is generally preferred over separate injections of MMR and varicella vaccines 1
Rationale for Two Doses
- Approximately 5% of children who receive only one dose of MMR vaccine fail to develop immunity to measles 1
- The second dose is primarily intended to induce immunity in those who did not respond to the first dose rather than to boost waning immunity 1
- Two doses ensure high levels of population immunity needed for measles elimination 3
- Studies show that after the second dose, seropositivity rates approach 99% for measles, mumps, and rubella 4, 5
Special Considerations
- A personal or family history (sibling or parent) of seizures of any etiology is a precaution for MMRV vaccination; in these cases, separate MMR and varicella vaccines are recommended 1
- The minimum interval between the first and second doses of MMR vaccine is 28 days (4 weeks) 1, 2
- Children who have already received two doses of MMR vaccine at least 28 days apart, with the first dose administered no earlier than the first birthday, do not need an additional dose when they enter school 1
Timing Considerations
- While both 4-6 years and 11-12 years have been recommended as timing for the second dose in the past, current guidelines favor the earlier administration at 4-6 years to ensure protection before school entry 1, 3
- Studies have shown that rubella antibody levels may decline by ages 11-13 years, suggesting potential benefits to the earlier second dose schedule 5
- The response to the second dose is high when administered to children in either age group, but earlier administration helps prevent school-based outbreaks 1, 3
The two-dose MMR vaccine schedule is essential for achieving and maintaining high population immunity and contributing to global measles elimination efforts 3.